Problem: Simplify the expression. $ (-7x^{4}-5x^{3}-7x) + (3x^{3}-3x^{2} ) $
Solution: Since we are adding polynomials, we can simply remove the parentheses. $-7x^{4}-5x^{3}-7x + 3x^{3}-3x^{2}$ Identify like terms. $ - {7 x^4} - \color{#DF0030}{5 x^3} - \color{#9D38BD}{7 x} + \color{#DF0030}{3 x^3} - {3 x^2} $ Combine like terms. $ { -7 x^4} + \color{#DF0030}{ x^3} + { -3 x^2} + \color{#9D38BD}{ -7 x} $ Add the coefficients. $-7x^{4}-2x^{3}-3x^{2}-7x$